.jpg)
Side Effect Match-Up: What Could Be Causing What?
You don’t need a food journal, just some light detective work. Here’s a quick cheat sheet:
Burping constantly?
You’re not imagining it! This is one of the top GLP-1 side effects, and it’s not just standard gas. Because your stomach empties more slowly on these meds, food hangs around longer than usual. That gives it more time to ferment, especially when you’ve had heavy, greasy, sugary, or ultra-processed foods, which can lead to trapped gas and those sulphuric burps that seem to appear out of nowhere.
There’s no instant fix, but you can make it easier on your system by leaning into simple, softer meals that break down more easily, like soups or stewed veg, and by swapping fizzy drinks for still ones. You don’t have to go bland, just gentler, especially on days where symptoms are showing up more than usual. It might not eliminate the burping completely, but it can take the edge off.
Sudden nausea?
Before you start blaming a specific food, ask yourself one question first: Did I actually eat enough today? A lot of nausea on GLP-1s comes from an empty stomach, not from overeating. It’s easy to go hours without food when your appetite’s gone, but that can make you feel worse, not better.
Once you’ve ruled that out, think about what you did eat. Rich, creamy, greasy, or super sweet foods tend to sit longer in the stomach, and without enough protein or fibre to balance them out, they can trigger that sudden wave of queasiness hours after eating.
Weird bloating or stomach pressure?
GLP-1 bloating isn’t always about volume, it can also be about timing and what your gut can handle right now. Even healthy foods can feel heavy if you eat more than your stomach’s ready for, especially after a long stretch without eating.
Meals that are too big, too rich, or too rushed can leave you feeling like you’ve swallowed a balloon. You might find that eating smaller portions more slowly, or spacing meals out across the day, gives your body more time to catch up and reduces that tight, uncomfortable pressure.
Heartburn or reflux?
This one can sneak up on you, especially if your usual meals are spicy, acidic, or high in fat. Slower digestion means those foods hang around longer, and that makes reflux more likely.
If heartburn is creeping in more often, try dialling back the heat or richness in your meals and give your body a bit more time before lying down after eating. Top tip: if reflux or heartburn is worse when you're lying down to sleep, try turning onto your left side. That’s because your stomach sits slightly to the left in your body, so lying on that side helps keep stomach acid lower in the digestive tract, instead of letting it creep up into your oesophagus. It’s a small shift that can make a big difference.
What to Try Instead
If a food left you feeling rough, don’t panic! It doesn’t mean you can never eat it again.
Try:
Eating smaller portions of the same food
Having it earlier in the day
Pairing it with something gentler (like carbs or protein)
Waiting until you’ve had a few bites of something else first
Or, you may find that you just have to go without that one for now.
TL;DR
GLP-1 side effects like nausea, bloating, burping, or reflux aren’t always about what you ate; they’re often about how your body processes it now. Greasy, sugary, or heavy meals tend to hang around longer and stir up symptoms, while lighter, simpler options usually go down easier.
But before you start cutting things out, make sure you’re not running on empty. Not eating enough is one of the most common and overlooked triggers. Pay attention, take notes, and adjust as needed. That’s how you build a rhythm that works for you.
The Repeat Offenders (And Why They Might Mess With You)
Once you’ve ruled out not eating, here are some foods that can make side effects worse, and a few ideas of why they act the way they do.
Greasy or fried foods
These take longer to digest and can sit heavily in your stomach, especially when digestion is already slowed down.
Think: chips, fried chicken, battered anything, or meals swimming in oil or butter. Even small portions can leave you nauseous, bloated, or waking up with stomach cramps hours later.
While you’re cutting back on these foods during your time on GLP-1s, it’s also a great chance to rethink how often they show up in your diet long-term. Not just because of side effects, but because they rarely leave you feeling good, full stop.
Big portions or heavy meals
When your appetite is reduced and digestion is slower, big meals can feel like a shock to the system. Even healthy food can backfire if you go from barely eating all day to trying to finish a full plate in one sitting.
The result? Nausea, burping, stomach pressure, or waking up in the night feeling like the food still hasn’t gone anywhere.
Try starting smaller and slowing down; your body will let you know when it’s had enough, and learning to hear that signal is one of the most valuable habits you can build while on GLP-1s.
Very sweet or sugary foods
Sugary foods might seem like an easy win when your appetite is low, but they can leave you feeling worse shortly after.
Some people report feeling lightheaded, jittery, or nauseous after things like fruit juice, pastries, sweets, or syrupy drinks, especially if eaten on their own.
While GLP-1s help regulate blood sugar overall, very sweet foods can still be hard on your system if there’s nothing else in your stomach. Ideally, try to avoid them altogether, but if you are having something sweet or sugary, try pairing it with some protein or fat to slow things down and make it easier on your body.
Carbonated drinks
Bubbles mean gas, and when digestion is slowed down, that gas can get trapped in the stomach. Cue: burping, bloating, and uncomfortable stomach pressure.
Fizzy drinks might feel refreshing, but they can leave you more uncomfortable than you expected, especially if your stomach is already sensitive or you're dealing with nausea.
That said, some people do say fizzy drinks help settle their stomach, especially ginger ale or citrus sodas in small sips. There's no real science behind it, but if you’ve found one that works for you and doesn’t make symptoms worse, trust your gut.
The key is noticing your body’s reaction and being willing to adjust. Not all bubbles are created equal.
High-fat dairy
Think: creamy cheeses, double cream, whole milk, buttery sauces.
High-fat dairy can be harder to digest, especially when paired with slower stomach emptying from GLP-1s. It tends to sit in the stomach longer, which can trigger nausea, bloating, or that "ugh, too much" feeling even after just a few bites.
Some people also notice an increase in burping or reflux after eating rich dairy, particularly when it’s eaten quickly or on an empty stomach.
If you’re finding dairy hits different lately, try switching to lighter versions (like Greek yoghurt or semi-skimmed milk) or reducing the portion size until you find your sweet spot.
Spicy foods
If your tolerance for spice has suddenly dropped, you’re not imagining it.
Spicy foods can irritate the stomach lining and increase acid production, which may be harder to handle when your digestion is slowed down. That can lead to nausea, reflux, or stomach cramps, even if you used to love a bit of heat.
It doesn’t mean you have to give up spice forever, but if your go-to meals are making you feel worse lately, try dialling it down for now. Milder versions of your favourites can still be satisfying without setting your stomach off.
It might not be what you ate... it might be what you didn’t
When your appetite’s already low, finally finding something that sounds good can feel like a win. But then you eat it... and five minutes later you’re bloated, burping, or curled up in a ball of regret. Sound familiar?
GLP-1 medications like Ozempic and Mounjaro slow down your digestion, so it’s not unusual for some foods to hit differently now. But here’s the part many people miss: Some side effects aren’t from what you ate, they’re from not eating enough in the first place.
So, before we start blaming the food, check in with this first:
Have you actually eaten a proper meal today?
Did you skip breakfast or forget lunch because you just “weren’t hungry”?
Are you running on two crackers and a cup of coffee?
Because here’s the truth: an empty stomach on GLP-1s often feels worse than a full one. Low blood sugar, no buffer for the medication, nothing to stabilise digestion, it’s a recipe for nausea, dizziness, and that heavy, uncomfortable gut feeling.
Start Here: Make Sure You’ve Eaten Enough
This is your first stop. If side effects hit suddenly or feel like they come out of nowhere, ask: “Have I actually eaten?”
Try starting with something small but nourishing, like:
A slice of toast
A banana and some Greek yoghurt
A protein smoothie or meal shake
Give it a little time. You might be surprised how quickly things calm down once your body has something to work with.
Bite-Sized Podcasts
Listen to this article as audio
.png)
Pen Hub Team
Published:
21 Jul 2025
Updated:
6 Oct 2025
Foods That Can Worsen the Side Effects of Weight Loss Jabs
Tuning In
.jpg)
Helpful Companions For Your Weight Loss Journey
From meal ideas to daily tracking, these digital tools are designed to make life on GLP-1s a little easier.
Related Articles
_edited.jpg)
Category
Heading 3
Category
Heading 3
Category
.jpg)